Bilateral master-slave arm control supported by computer systems should best utilize the merits of both human operators and computer systems. Our previous studies have shown that the operator can adjust the variable gain smoothly to change the connection between manual and automatic modes by force-sensed grips. In this paper, some improvements are proposed for the control method to maintain efficiency through estimation of parameters and application of fuzzy rules. The driving force of the actuator is adjusted according to the estimated parameters of the working environment in the sliding mode control. Then, the fuzzy rules are applied to determine the manipulated force given to the bilateral control system so that the skilled technique of a human operator can be incorporated into computer operation. Because the computer moves the slave arm in a similar manner as the human operator does, it becomes simple for the operator to understand the motion of the slave arm and easy to intervene in the computer operations. Through some actual trials in a one-degree-of-freedom arm, this proposed method is proven to be practical in the operation of a master-slave arm even though information for the assigned jobs was not complete.